JP3406773B2 - Silicone rubber composition for fluorine resin coated fixing roll and fluorine resin coated fixing roll - Google Patents

Description

Detailed Description of the Invention

[0001]

TECHNICAL FIELD The present invention relates to a fluororesin-coated fixing roll for silicone rubber compositions and relates to a fluororesin-coated fixing roll, more particularly, 70 that does not cause wrinkles in the fluororesin layer of the fluorine resin coated fuser roll surface 1
TECHNICAL FIELD The present invention relates to a silicone rubber composition for a fluororesin-coated fixing roll capable of forming a silicone rubber having excellent adhesion to a roll shaft and a fluororesin layer even when cured at a relatively low temperature of 40 ° C. , and a highly reliable fluororesin-coated fixing roll. .

[0002]

2. Description of the Related Art A fluororesin-coated fixing roll comprising a metal roll shaft and a fluororesin layer provided on the outer peripheral surface of the roll shaft via a silicone rubber layer having a relatively low hardness has excellent toner releasability.
It is suitable for use in electrophotographic copying machines, printers, facsimiles, etc. because it can be downsized (Japanese Patent Application Laid-Open No. Sho 5).
3-74436, JP-A-57-89785, JP-A-59-74578, and JP-A-59.
-52269 gazette).

In this fluororesin-coated fixing roll, generally, a roll shaft whose outer peripheral surface is preliminarily treated is inserted into a fluororesin tube, and a silicone rubber composition is pressed into a cavity between the roll shaft and the tube. It is created by curing. At this time, in order to sufficiently bond the roll shaft and the fluororesin layer to the silicone rubber layer, it is necessary to cure the silicone rubber composition at a relatively high temperature, for example, 150 to 200 ° C. Due to the difference in the coefficient of thermal expansion between the silicone rubber composition and the fluororesin, there often occurs a problem that the fluororesin layer on the surface of the obtained fluororesin-coated fixing roll is wrinkled. This problem is relatively low hardness, for example, JIS
It was particularly remarkable in a silicone rubber composition forming a silicone rubber having an A hardness of 20 or less.

On the other hand, when the silicone rubber composition is cured at a relatively low temperature, for example, 80 to 120 ° C. so that the fluororesin layer on the surface of the fluororesin-coated fixing roll does not wrinkle, the composition is cured. There is a problem that the adhesiveness to the roll shaft and the fluororesin layer which are in contact with each other on the way is inferior, and even if the roll shaft and the fluororesin layer are previously treated with a primer, these adhesive properties are not so improved. Therefore, wrinkles do not occur in the fluororesin layer on the surface of the fluororesin-coated fixing roll prepared by curing the silicone rubber composition at a relatively low temperature, but the roll shaft and the interface between the fluororesin layer and the silicone rubber layer are separated. There is a problem that it is easy to do and inferior in reliability.

[0005]

DISCLOSURE OF THE INVENTION As a result of diligent studies on the above-mentioned problems, the present inventors have found that at least 2 molecules are contained in one molecule.
Even if an addition reaction-curing type silicone rubber composition containing a specific amount of a cyclic diorganopolysiloxane containing a silicon-bonded alkenyl group is cured at a relatively low temperature of 70 to 140 ° C., it is still in contact during curing. The present invention has been accomplished by finding that a silicone rubber having good adhesion to the roll shaft and the fluororesin layer can be formed.

That is, the object of the present invention is to provide adhesiveness to the roll shaft and the fluororesin layer even when cured at a relatively low temperature of 70 to 140 ° C. so that the fluororesin layer on the surface of the fluororesin-coated fixing roll is not wrinkled. It is intended to provide a silicone rubber composition for a fluororesin-coated fixing roll capable of forming a good silicone rubber, and further to provide a fluororesin-coated fixing roll having excellent reliability.

[0007]

The silicone rubber composition for a fluororesin-coated fixing roll according to the present invention has a roll shaft outer periphery.
Do not provide a fluororesin layer on the surface with a silicone rubber layer.
Silicone rubber layer in fluororesin-coated fixing roll
A silicone rubber composition for forming a low
At least consists of (A) to (E) below, and the outer circumference of the roll shaft
To be cured at 70-140 ° C between the surface and the fluororesin layer
Is characterized in that. (A) 100 parts by weight of linear diorganopolysiloxane containing at least two silicon-bonded alkenyl groups in one molecule, (B) 5 to 500 parts by weight of inorganic filler, (C) at least one molecule. Cyclic diorganopolysiloxane containing two silicon-bonded alkenyl groups 0.005 to 5 parts by weight, (D) Organopolysiloxane containing at least two silicon-bonded hydrogen atoms in one molecule {(A) Ingredients and
(C) Amount in which the molar ratio of silicon atom-bonded hydrogen atoms in component (D) to the total amount of silicon atom-bonded alkenyl groups in component (D) is 0.1-10}, and (E) platinum-based catalyst , fluororesin coated fixing roll of the present invention is the fluororesin coating fixing roll made by providing a fluororesin layer through the silicone rubber layer on the outer circumferential surface of the roll shaft, roll shaft
The silicone according to claim 1, which is between the outer peripheral surface and the fluororesin layer.
The rubber composition has been cured at 70 to 140 ° C.
And are characterized.

[0008]

BEST MODE FOR CARRYING OUT THE INVENTION First, the fluororesin-coated silicone rubber composition for a fixing roll of the present invention will be described in detail. The component (A) is the main component of the present composition and is a linear diorganopolysiloxane containing at least two silicon-bonded alkenyl groups in one molecule. The molecular structure of the component (A) is substantially linear, but it may have a branched chain in a part of the main chain. The component (A) must contain at least two silicon atom-bonded alkenyl groups in one molecule, in order to sufficiently cure the composition.
Although the bonding position of the silicon atom-bonded alkenyl group in the component (A) is not limited, since the compression set of the obtained silicone rubber can be made particularly small, the average number of silicon atom bonds in the side chains of the molecule is 0.5 or more. It is preferable that an alkenyl group is bonded. Examples of the silicon atom-bonded alkenyl group in the component (A) include a vinyl group, an allyl group, a butenyl group, a pentenyl group, a hexenyl group and a heptenyl group, and a vinyl group and a hexenyl group are particularly preferable. Examples of the group bonded to a silicon atom other than the alkenyl group in the component (A) include an alkyl group such as a methyl group, an ethyl group, a propyl group, a butyl group, a pentyl group, and a hexyl group; a phenyl group, a tolyl group, and a xylyl group. Aryl groups such as groups; aralkyl groups such as benzyl and phenethyl groups; 3-
Examples thereof include halogenated alkyl groups such as chloropropyl group and 3,3,3-trifluoropropyl group; alkoxy groups such as methoxy group and ethoxy group; and hydroxyl group, with methyl group being particularly preferred. The viscosity of the component (A) at 25 ° C. is preferably 1,000 centipoise or more, and more preferably 1,000 to 1,000,000.
It is preferably in the range of 0 centipoise, and particularly preferably in the range of 10,000 to 500,000 centipoise.

Examples of the component (A) include dimethylpolysiloxane capped with dimethylvinylsiloxy groups at both ends of the molecular chain, dimethylsiloxane-methylphenylsiloxane copolymer capped with dimethylvinylsiloxy groups at both ends of the molecular chain, and dimethylpolysiloxane at both ends of the molecular chain. Vinylsiloxy group-blocked dimethylsiloxane-methyl (3,3,3-trifluoropropyl) siloxane copolymer, molecular chain both ends trimethylsiloxy group-blocked methylvinylsiloxane-dimethylsiloxane copolymer, molecular chain both ends trimethylsiloxy group-blocked Methyl vinyl polysiloxane, both ends of molecular chain trimethylsiloxy group-blocked methyl vinyl siloxane / methyl phenyl siloxane copolymer, both ends of molecular chain trimethyl siloxy group blocked methyl vinyl siloxane / dimethyl siloxane / methyl phenyl siloxa Copolymer, dimethylsiloxy group-capped methylvinylsiloxane / dimethylsiloxane / methyl (3,3,3-trifluoropropyl) siloxane copolymer at both ends of the molecular chain Copolymer, dimethylvinylsiloxy group-blocked methylvinylsiloxane / dimethyl at both ends of the molecular chain Siloxane copolymer, dimethylvinylsiloxy group-blocked methylvinylpolysiloxane at both molecular chain ends, dimethylvinylsiloxy group-blocked methylvinylsiloxane at both molecular chain terminals, methylphenylsiloxane copolymer, dimethylvinylsiloxy group-blocked methylvinyl at both molecular chain ends Siloxane / dimethyl siloxane / methyl phenyl siloxane copolymer, molecular chain both ends silanol group blocked methyl vinyl siloxane / dimethyl siloxane copolymer, molecular chain both ends silanol group blocked methyl vinyl polysiloxane, molecule Methyl vinyl siloxane / dimethyl siloxane / methylphenyl siloxane copolymer with both ends of the chain silanol group, methyl vinyl siloxane / dimethyl siloxane / methyl (3,3,3-trifluoropropyl) siloxane copolymer with both ends of the molecule chain silanol group The above linear diorganopolysiloxanes may be used alone or in combination of two or more. In addition, a linear diorganopolysiloxane containing no silicon atom-bonded alkenyl groups in the side chains of the molecular chain and a linear diorganopolysiloxane containing silicon atom-bonded alkenyl groups in the side chain of the molecule are mixed to form a molecule. A linear diorganopolysiloxane containing an average of 0.5 or more silicon atom-bonded alkenyl groups in the side chains may be used.

The component (B) is an inorganic filler for imparting mechanical strength, thermal conductivity or conductivity to the silicone rubber obtained by curing the composition. like this
As the component (B), precipitated silica fine powder, fumed silica fine powder, calcined silica fine powder, fumed titanium oxide fine powder, ground quartz fine powder, diatomaceous earth fine powder, aluminosilicate fine powder, iron oxide fine powder, Examples include zinc oxide fine powder, calcium carbonate fine powder, carbon black fine powder, alumina fine powder, aluminum hydroxide fine powder, silver fine powder, and nickel fine powder. These inorganic fillers may be used alone or in combination of two or more. Good. The component (B) may be blended as it is, or the surface of the component (B) may be preliminarily surface-treated with an organosilicon compound such as organoalkoxysilane, organochlorosilane, or organodisilazane. Alternatively, the component (B) may be blended in the component (A) while surface-treating it with these organosilicon compounds.

The blending amount of the component (B) is in the range of 5 to 500 parts by weight with respect to 100 parts by weight of the component (A), and particularly 1
It is preferably in the range of 0 to 300 parts by weight. This is because if the blending amount of the component (B) with respect to 100 parts by weight of the component (A) is less than 5 parts by weight, the mechanical strength of the obtained silicone rubber will be poor, and this will exceed 500 parts by weight. This makes it difficult to uniformly mix the component (B) with the silicone rubber composition.

[0012] Component (C), the composition such that no wrinkles in the fluororesin layer of the fluorine resin coated fuser roll surface 7
It is a component for forming a silicone rubber having good adhesion to the roll shaft and the fluororesin layer even when cured at a relatively low temperature of 0 to 140 ° C. , and contains at least two silicon atom-bonded alkenyl groups in one molecule. The contained cyclic diorganopolysiloxane. Such a component (C) has a general formula:

[Chemical 3] It is preferable that the cyclic diorganopolysiloxane represented by R ¹ in the above formula is the same or different monovalent hydrocarbon group excluding alkenyl group, and is an alkyl group such as methyl group, ethyl group, propyl group, butyl group, pentyl group, hexyl group; phenyl group, tolyl group. Group, aryl group such as xylyl group; aralkyl group such as benzyl group and phenethyl group; halogenated alkyl group such as 3-chloropropyl group, 3,3,3-trifluoropropyl group, and the like, particularly methyl group, It is preferably a phenyl group. R ² in the above formula is an alkenyl group, and examples thereof include a vinyl group, an allyl group, a butenyl group, a pentenyl group, a hexenyl group, and a heptenyl group, with a vinyl group and a hexenyl group being particularly preferable. Further, m in the above formula is an integer of 2 to 20, preferably 3 to 20. Further, n in the above formula is an integer of 0 to 18, and preferably,
It is an integer of 0 to 17. Also, m + n in the above formula is 3 to 2
It is an integer of 0, preferably an integer of 4 to 10.

As the component (C), 1, 3, 5
-Trimethyl-1,3,5-trivinylcyclotrisiloxane, 1,3,5,7-tetramethyl-1,3,5
7-tetravinylcyclotetrasiloxane, 1,3
5,7,9-Pentamethyl-1,3,5,7,9-pentavinylcyclopentasiloxane, 1,3,5-trimethyl-1,3,5-trihexenylcyclotrisiloxane, 1,3,5 7-Tetramethyl-1,3,5,7-
Tetrahexenyl cyclotetrasiloxane, 1,3
In addition to cyclic methylalkenylpolysiloxanes such as 5,7,9-pentamethyl-1,3,5,7,9-pentahexenylcyclopentasiloxane, cyclic methylvinylsiloxane / dimethylsiloxane copolymers, cyclic methylhexenylsiloxane. Dimethyl siloxane copolymer, cyclic methyl vinyl siloxane / methyl phenyl siloxane copolymer, cyclic methyl vinyl siloxane / methyl (3
3,3-trifluoropropyl) siloxane copolymer is exemplified, and these cyclic diorganopolysiloxanes may be used alone or in combination of two or more kinds.

The blending amount of the component (C) is in the range of 0.005 to 5 parts by weight, particularly 0.01 to 0.5 parts by weight, relative to 100 parts by weight of the component (A). Preferably there is. This is because the silicone rubber composition in which the amount of the component (C) is less than 0.005 parts by weight relative to 100 parts by weight of the component (A) prevents wrinkles from being generated in the fluorine resin layer on the surface of the fixing roll coated with the fluorine resin. This is because the silicone rubber cured at a relatively low temperature of 70 to 140 ° C. does not have sufficient adhesiveness to the roll shaft and the fluororesin layer, and the silicone rubber composition having more than 5 parts by weight is
This is because the curability is reduced.

The component (D) is a crosslinking agent for curing the composition, and is an organopolysiloxane containing at least two silicon-bonded hydrogen atoms in one molecule.
Examples of the molecular structure of the component (D) include linear, partially branched linear, branched, cyclic, and net-like, and particularly linear and partially branched linear. Is preferred.
Such a component (D) has a general formula:

[Chemical 4] The organopolysiloxane represented by is preferable. R ¹ in the above formulas are the same or different monovalent hydrocarbon groups excluding the alkenyl group, and the same monovalent hydrocarbon groups as those mentioned above are exemplified, and particularly preferably a methyl group or a phenyl group. Further, R ³ in the above formula except for alkenyl groups are the same or different monovalent hydrocarbon group or a hydrogen atom, a monovalent hydrocarbon group R ^3, the same monovalent hydrocarbon as the R ¹ Examples thereof include a group, and a methyl group and a phenyl group are particularly preferable. Also, p in the above equation is 0
It is an integer above the above. Further, q in the above formula is an integer of 0 or more. However, when q in the above formula is 0, it is necessary that both R ³ are hydrogen atoms. Also, p + q in the above equation
Is not limited, but is preferably an integer in the range of 5 to 1000, and more preferably an integer in the range of 5 to 100. Further, the viscosity of the component (D) at 25 ° C. is preferably in the range of 3 to 10,000 centipoise, and particularly preferably in the range of 3 to 300 centipoise.

Examples of the component (D) include methyl hydrogen polysiloxane capped with trimethylsiloxy groups at both ends of the molecular chain, dimethylsiloxane-methyl hydrogen siloxane copolymer capped with trimethylsiloxy groups at both ends of the molecular chain, and both ends of the molecular chain. Examples include dimethylhydrogensiloxy group-blocked methylhydrogenpolysiloxane, dimethylhydrogensiloxy group-blocked dimethylpolysiloxane at both molecular chain ends, and dimethylhydrogensiloxy group-blocked dimethylsiloxane-methylhydrogensiloxane copolymer at both molecular chain ends. You may mix these organopolysiloxane individually or in 2 or more types.

The amount of the component (D) blended is such that the molar ratio of silicon atom-bonded hydrogen atoms in the component (D) to the total amount of alkenyl groups in the components (A) and (C) is 0.1 to 10. The amount is within the range, and particularly preferably the amount is within the range of 0.3 to 5. This is because the composition in which the molar ratio of silicon atom-bonded hydrogen atoms in the component (D) to the total amount of alkenyl groups in the components (A) and (C) is less than 0.1 does not cure sufficiently. The composition containing more than 10 has bubbles in the obtained silicone rubber,
The hardness is significantly increased, and the hardness is relatively low, that is,
This is because it is often not preferable for a fluororesin-coated fixing roll that requires a silicone rubber having a JIS A hardness of 20 or less.

The component (E) is a platinum-based catalyst for promoting curing of the composition. Examples of the component (E) include platinum black, platinum-supported alumina powder, platinum-supported silica powder, platinum-supported carbon powder, chloroplatinic acid, alcohol solution of chloroplatinic acid, platinum-olefin complex, platinum-vinyl. Examples thereof include complexes with siloxane, and fine powders obtained by dispersing these platinum-based catalysts in a thermoplastic organic resin such as methyl methacrylate resin, polycarbonate resin, polystyrene resin, and silicone resin.

The amount of the component (E) to be blended is a catalytic amount, and may be an amount sufficient to cure the present composition.
The amount of platinum metal in the component (E) is preferably in the range of 0.01 to 1,000 parts by weight with respect to 1 million parts by weight of the component (A), and particularly 0.1 to 500 parts by weight. The amount is preferably within the range of parts.

The composition of the present invention may further contain other optional components such as 3-methyl-1-butyn-3-ol and 3,5-dimethyl-1 in order to improve storage stability and handleability. -Hexyne-3-ol, 3-phenyl-1
-Acetylenic compounds such as butyn-3-ol; 3-methyl-3-penten-1-yne, 3,5-dimethyl-3
It is preferable to add an enyne compound such as -hexen-1-yne; and a curing inhibitor such as phosphines, mercaptans and hydrazines. The compounding amount of these curing inhibitors is preferably in the range of 0.001 to 5 parts by weight with respect to 100 parts by weight of the component (A).

The composition of the present invention may further contain, as an optional component, a linear diorganopolysiloxane containing no silicon atom-bonded alkenyl groups and silicon atom-bonded hydrogen atoms for controlling the hardness of the resulting silicone rubber. It is preferable to mix them. The molecular structure of this diorganopolysiloxane is substantially linear, but it may have a branched chain in part of its main chain. Examples of the group bonded to the silicon atom of this diorganopolysiloxane include an alkyl group such as a methyl group, an ethyl group, a propyl group, a butyl group, a pentyl group and a hexyl group; an aryl group such as a phenyl group, a tolyl group and a xylyl group; An aralkyl group such as a benzyl group and a phenethyl group; a halogenated alkyl group such as a 3-chloropropyl group and a 3,3,3-trifluoropropyl group; an alkoxy group such as a methoxy group and an ethoxy group; and a hydroxyl group.
It is preferably a methyl group or a phenyl group. Further, the viscosity of this linear diorganopolysiloxane at 25 ° C. is 100 centipoise or more because the obtained silicone rubber composition has a good workability in handling and can produce a good fluororesin-coated fixing roll. Is preferred, and in particular, 1,000 to 10,000,
It is preferably in the range of 000 centipoise.

Examples of such a straight chain diorganopolysiloxane include dimethylpolysiloxane endcapped with trimethylsiloxy groups at both molecular chain ends, dimethylsiloxane / methylphenylsiloxane copolymer endblocked with trimethylsiloxy groups at both molecular chain ends, and both molecular chain ends. Trimethylsiloxy group-blocked dimethylsiloxane / methyl (3,3,3-trifluoropropyl) siloxane copolymer, molecular chain both-terminals silanol group-blocked dimethylpolysiloxane, molecular chain both-terminals silanol group-blocked dimethylsiloxane / methylphenylsiloxane copolymer Coalescence, silanol group-capped dimethylsiloxane methyl (3,3,3-trifluoropropyl) at both ends of the molecular chain
A siloxane copolymer is exemplified, and these linear diorganopolysiloxanes may be blended alone or in combination of two or more.

The amount of the linear diorganopolysiloxane blended is sufficient to reduce the hardness of the silicone rubber, and to prevent the silicone rubber from seeping out, the component (A) is used. It is preferably in the range of 5 to 100 parts by weight with respect to 100 parts by weight,
In particular, it is preferably in the range of 10 to 50 parts by weight.

In order to further reduce the compression set of the silicone rubber obtained by curing this composition, the composition contains, for example, a ring of pyridine, pyrazine, pyrimidine, 1,3,5-triazine or the like. It is preferable to incorporate an extremely small amount of a 6-membered ring compound having a carbon-nitrogen unsaturated bond therein or a derivative thereof. In addition, the present composition may also include other known pigments, heat resistance-imparting agents such as iron oxide, cerium siloxanate and calcium hydroxide, and flame-retardant agents such as fumed titanium dioxide, if necessary. It can be blended within a range that does not impair the purpose.

The composition comprises the above-mentioned components (A) to (E),
And, if necessary, it is prepared by uniformly mixing other optional components. As a method for preparing the present composition, for example, the above-mentioned components (A) to (E) and, if necessary, other optional components are two-roll, kneader mixer, Henschel mixer, flow jet mixer, helical A method of uniformly mixing with a known kneading device such as a rotor mixer may be used.

Next, the fluororesin-coated fixing roll of the present invention will be described in detail. The fluororesin-coated fixing roll according to the present invention is shown in FIG. As shown in FIG. 1, the fluororesin-coated fixing roll of the present invention is provided with a fluororesin layer 3 on the outer peripheral surface of a roll shaft 1 with a silicone rubber layer 2 interposed therebetween. It is characterized by being formed by curing a rubber composition. The thickness of the fluororesin layer 3 is preferably 0.1 mm or less, and particularly preferably 0.1 to 50 μm. The material of the fluororesin layer 3 is polytetrafluoroethylene resin (PTFE), tetrafluoroethylene / perfluoroalkyl vinyl ether copolymer resin (PFA), fluorinated ethylene / polypropylene copolymer resin (FEP). ), Tetrafluoroethylene / ethylene copolymer resin (ETFE), polychlorotrifluoroethylene copolymer resin (PCTFE), polyvinylidene fluoride resin (PVDF), polyvinyl fluoride resin
(PVF), ethylene trifluorochloride / ethylene copolymer resin (ECTFE), and tetrafluoroethylene / hexafluoropropylene copolymer resin (FEP) are exemplified. The thickness of the silicone rubber layer 2 is 2 to 30 mm.
Is preferred.

As a method for producing the fixing roll of the present invention, for example, a metal roll shaft 1 made of iron or aluminum is placed inside the roll forming die, and the roll forming die A method may be mentioned in which a fluororesin tube is placed on the inner wall, then the silicone rubber composition is press-fitted into the cavity between the roll shaft and the fluororesin tube, and then cured. In order to further improve the adhesiveness between the roll shaft 1 and the fluororesin layer 3 and the silicone rubber layer 2, it is preferable that the outer peripheral surface of the roll shaft and the inner peripheral surface of the fluororesin tube are pre-treated. As a method for press-fitting the silicone rubber composition into the cavity between the roll shaft 1 and the fluororesin tube, a compression molding machine, a transfer molding machine, or an injection molding machine that is usually used when molding a liquid silicone rubber composition is used. be able to. Further, if the curing temperature of the silicone rubber composition is extremely low, the curing rate will be slow, and the productivity of the fluororesin-coated fixing roll will be significantly reduced. If the curing temperature is extremely high, the fluororesin obtained will be obtained. Since the fluororesin layer 3 on the surface of the coating fixing roll has wrinkles, the curing temperature is 70 to 140 ° C.
Is preferably in the range of 90 to 120 ° C.
It is preferably within the range. Further, in order to further reduce the compression set rate of the silicone rubber obtained by curing at a relatively low temperature, this is further reduced to 150 to 250.
It is preferable to heat-treat at ° C. Even if this heat treatment is performed, since the coefficient of thermal expansion of the silicone rubber is smaller than that of the composition before curing, wrinkles do not occur in the fluororesin layer 3 on the surface of the fluororesin-coated fixing roll.

The fluororesin-coated fixing roll of the present invention as described above has excellent reliability, that is, the adhesiveness between the roll shaft 1 and the fluororesin layer 3 and the silicone rubber layer 2 is good, so that the electrophotographic copying machine, It is suitable as a fixing roll for printers, facsimiles and the like.

[0029]

EXAMPLES The silicone rubber composition for a fluororesin-coated fixing roll and the fluororesin-coated fixing roll of the present invention will be described in detail with reference to Examples. The viscosity in the examples is 25.
It is a value measured at ° C. The silicone rubber was evaluated as follows. [Hardness of Silicone Rubber] The silicone rubber composition was cured by a hot press machine at 120 ° C. for 30 minutes. The obtained silicone rubber was further heat-treated in an oven at 200 ° C. for 4 hours. The hardness of the silicone rubber thus obtained is determined according to JIS K
6301 was measured by a JIS A hardness meter. [Compression Set of Silicone Rubber] The silicone rubber composition was cured by a hot press machine at 120 ° C. for 30 minutes. The obtained silicone rubber was further heat-treated in an oven at 200 ° C. for 4 hours. The compression set of the silicone rubber thus obtained was measured according to the compression set test method specified in JIS K6301. The heat treatment temperature during the compression test is 1
The temperature was 80 ° C., and the heat treatment time was 22 hours. [Adhesiveness of Silicone Rubber] A commercially available primer was uniformly applied to the surface of an aluminum test panel, and this was applied in an oven at 150 ° C. for 30 minutes.
The primer was thoroughly dried by leaving it for a minute. After applying the silicone rubber composition to this test panel, 100
The mixture was cured for 30 minutes by a heating press machine at 0 ° C. to adhere the silicone rubber. Then pull the silicone rubber in the direction of 90 ° to the plane of the test panel,
The ratio of the adhesion area of the part where the silicone rubber was cohesively destroyed (cohesion failure rate) was determined. Further, the cohesive failure rate when the curing temperature was 150 ° C. was also obtained in the same manner. Further, a commercially available primer was uniformly applied to a fluororesin (tetrafluoroethylene / perfluoroalkylperfluorovinylether copolymer) film whose surface was treated with an alkali, and then the primer was sufficiently dried by leaving it at room temperature for 1 hour. . The adhesiveness of the silicone rubber to this fluororesin film was evaluated in the same manner as above. [Volume Resistivity of Silicone Rubber] The volume resistivity of the silicone rubber prepared by the above method was measured according to the volume resistivity test method specified in JIS C 2123.

Example 1 With a kneading machine, the viscosity was 40,000 centipoise and the formula:

[Chemical 5] 100 parts by weight of a methylvinylsiloxane / dimethylsiloxane copolymer capped with trimethylsiloxy groups at both ends of the molecular chain represented by and a finely ground quartz powder 30 having an average particle diameter of 5 μm After uniformly mixing the parts by weight, add to this the formula:

[Chemical 6] 0.05 parts by weight of cyclic methyl vinyl polysiloxane represented by the formula, viscosity is 38 centipoise, and formula:

[Chemical 7] Dimethylpolysiloxane having a dimethylhydrogensiloxy group blocked at both terminals of the molecular chain (content of hydrogen atoms bonded to silicon atom = 0.065% by weight) 6 parts by weight (the above-mentioned methylvinylsiloxane-dimethylsiloxane copolymer and cyclic) The molar ratio of silicon-bonded hydrogen atoms in this dimethylpolysiloxane to the total amount of vinyl groups in the methylvinylpolysiloxane is 0.8.), And chloroplatinic acid in isopropyl alcohol (platinum metal content = 0.5 parts by weight (1% by weight) were uniformly mixed to prepare a silicone rubber composition.

The hardness (JIS A) of the silicone rubber obtained by curing this silicone rubber composition is 5,
The compression set was 5%. The cohesive failure rate of the silicone rubber against the aluminum test panel and the fluororesin film was 100 ° C.
And 100% at any curing temperature of 150 ° C
Met.

A commercially available primer was uniformly applied to the outer peripheral surface of a cylindrical iron roll shaft having a diameter of 10 mm, and the primer was sufficiently dried by leaving it in an oven at 150 ° C. for 30 minutes. Also, the inner surface is alkali-treated, and the film thickness is 50
A commercially available primer was uniformly applied on the inner surface of a tetrafluoroethylene / perfluoroalkyl perfluorovinyl ether copolymer tube having a thickness of μm, and the primer was sufficiently dried by leaving it at room temperature for 1 hour. Next, the roll shaft is placed inside the roll forming die, and the tube is placed on the inner wall of the die. Then, the silicone rubber composition is placed in the cavity between the roll shaft and the tube. After press-fitting, press this at 100 ° C for 30
It was cured in minutes to prepare a fluororesin-coated fixing roll having a wall thickness of 10 mm. The fluororesin layer on the surface of the fluororesin-coated fixing roll was observed, but no wrinkles were formed. Further, when the adhesiveness between the roll shaft and the fluororesin layer and the silicone rubber layer was observed, the adhesiveness was good. Then, the fluororesin-coated fixing roll
When heat-treated in an oven at 00 ° C. for 4 hours, no wrinkles were formed in the fluororesin layer on the surface of the fluororesin-coated fixing roll. This fluororesin-coated fixing roll was mounted on an electrophotographic copying machine to continuously copy 150,000 sheets of A4 size copying paper, but there were no paper wrinkles or paper jams.
The image was clearly copied. When the fluororesin-coated fixing roll was cured by curing at 150 ° C. for 30 minutes, wrinkles were formed in the fluororesin layer on the surface of the fluororesin-coated fixing roll.

Comparative Example 1 A silicone rubber composition was prepared in the same manner as in Example 1 except that the cyclic methylvinylpolysiloxane was not added. The silicone rubber obtained by curing this silicone rubber composition had a hardness (JIS A) of 6 and a compression set of 5%. The cohesive failure rate of this silicone rubber is 20% at a curing temperature of 100 ° C. and 10% at a curing temperature of 150 ° C.
It was 0%. Using this silicone rubber composition, a fluororesin-coated fixing roll was prepared in the same manner as in Example 1.
This fluororesin-coated fixing roll is 30 at 100 ° C.
It was made to cure in minutes. Wrinkles were not formed in the fluororesin layer on the surface of the fluororesin-coated fixing roll, but partial peeling was observed at the roll shaft and at the interface between the fluororesin layer and the silicone rubber layer. 150 ° C
When a fluororesin-coated fixing roll was prepared by curing in 30 minutes, a wrinkle was found in the fluororesin layer on the surface of the fluororesin-coated fixing roll.

Example 2 With a kneading device, the viscosity was 40,000 centipoise and the formula:

[Chemical 8] 100 parts by weight of a dimethylvinylsiloxy group-blocked methylvinylsiloxane / dimethylsiloxane copolymer having molecular chains at both ends represented by (vinyl group content = 0.16% by weight),
15 parts by weight of pulverized quartz fine powder having an average particle diameter of 5 μm,
And 8 parts by weight of carbon black (Denka Acetylene Black manufactured by Denki Kagaku Kogyo Co., Ltd.) were uniformly mixed, and then the formula:

[Chemical 9] Cyclic methylhexenyl polysiloxane represented by 0.1
By weight, the viscosity is 10 centipoise and the formula:

[Chemical 10] 5 parts by weight of the above-mentioned dimethylsiloxane / methylhydrogensiloxane copolymer capped with trimethylsiloxy groups at both molecular chain ends (content of hydrogen atoms bonded to silicon atoms = 0.24% by weight) (the above-mentioned methylvinylsiloxane / dimethylsiloxane) (The molar ratio of silicon atom-bonded hydrogen atoms in this dimethylsiloxane-methylhydrogensiloxane copolymer to the total amount of vinyl groups and hexenyl groups in the copolymer and cyclic methylhexenyl polysiloxane is 1.8.) , And an isopropyl alcohol solution of chloroplatinic acid (platinum metal content = 1% by weight).
A silicone rubber composition was prepared by uniformly mixing 5 parts by weight.

The silicone rubber obtained by curing this silicone rubber composition has a hardness (JIS A) of 12, a volume resistivity of 1 × 10 ⁴ Ω · cm, and a compression set of 8%. there were. The cohesive failure rate of the silicone rubber on the aluminum test panel and the fluororesin film was 100% at both the curing temperature of 100 ° C and 150 ° C.

Using this silicone rubber composition, a fluororesin-coated fixing roll was prepared in the same manner as in Example 1. When this fluororesin-coated fixing roll was cured by curing at 100 ° C. for 30 minutes, no wrinkles were formed on the fluororesin layer on the surface of the fluororesin-coated fixing roll. The adhesiveness between the roll shaft and the fluororesin layer and the silicone rubber layer was good. Next, this fluororesin-coated fixing roll was heat-treated at 200 ° C. for 4 hours, but no wrinkles were formed on the fluororesin layer on the surface of the fluororesin-coated fixing roll. This fluororesin-coated fixing roll was mounted in an electrophotographic copying machine to continuously copy 150,000 sheets of A4 size copying paper, but there was no paper wrinkle or paper jam, and the image was clearly copied. 1
When the fluororesin-coated fixing roll was cured by curing at 50 ° C. for 30 minutes, wrinkles were formed in the fluororesin layer on the surface of the fluororesin-coated fixing roll.

Comparative Example 2 A silicone rubber composition was prepared in the same manner as in Example 2 except that the cyclic methylhexenyl polysiloxane was not added. The silicone rubber obtained by curing this silicone rubber composition has a hardness (JIS A) of 11, and a volume resistivity of 1 × 10 ⁴ Ω · cm,
The compression set was 8%. The cohesive failure rate of this silicone rubber is 5 at a curing temperature of 100 ° C.
0% and 100% at a curing temperature of 120 ° C. Using this silicone rubber composition, Example 1
A fluororesin-coated fixing roll was prepared in the same manner as in. 1
Wrinkles did not occur on the fluororesin layer on the surface of the fluororesin-coated fixing roll prepared by curing at 00 ° C. for 30 minutes, but some peeling occurred on the roll shaft and the interface between the fluororesin layer and the silicone rubber layer. Was observed. When the fluororesin-coated fixing roll was cured by curing at 150 ° C. for 30 minutes, wrinkles were formed in the fluororesin layer on the surface of the fluororesin-coated fixing roll.

[0038]

EFFECTS OF THE INVENTION The silicone rubber composition for a fluororesin-coated fixing roll of the present invention is 70 to 140 ° C. so that the fluororesin layer on the surface of the fluororesin-coated fixing roll is free from wrinkles.
That is , the silicone rubber having good adhesion to the roll shaft and the fluororesin layer can be formed even when cured at a relatively low temperature. The fluororesin-coated fixing roll of the present invention uses such a silicone rubber composition. Since it is created with the following features, it is characterized by excellent reliability.

[Brief description of drawings]

FIG. 1 is a sectional view of a fluororesin-coated fixing roll according to the present invention.

[Explanation of symbols]

1 roll axis 2 Silicone rubber layer 3 Fluororesin layer

─────────────────────────────────────────────────── ─── Continuation of the front page (56) Reference JP-A-4-359059 (JP, A) JP-A-6-95545 (JP, A) JP-A-6-316690 (JP, A) JP-A-8- 48885 (JP, A) (58) Fields investigated (Int. Cl. ⁷ , DB name) C08L 83/07 C08L 83/05

Claims (5)

(57) [Claims] 1. A silicone rubber layer is provided on the outer peripheral surface of a roll shaft.
Fluororesin coated fixing roller with a fluororesin layer
Silicone for forming silicone rubber layer in
A rubber composition having at least the following (A) to
(E) between the outer peripheral surface of the roll shaft and the fluororesin layer
Characterized by being cured at 70 to 140 ° C
Silicone rubber composition for fixing roll coated with fluororesin. (A) 100 parts by weight of linear diorganopolysiloxane containing at least two silicon-bonded alkenyl groups in one molecule, (B) 5 to 500 parts by weight of inorganic filler, (C) at least one molecule. Cyclic diorganopolysiloxane containing two silicon-bonded alkenyl groups 0.005 to 5 parts by weight, (D) Organopolysiloxane containing at least two silicon-bonded hydrogen atoms in one molecule {(A) Ingredients and
(C) Amount in which the molar ratio of silicon atom-bonded hydrogen atoms in component (D) to the total amount of silicon atom-bonded alkenyl groups in component (D) is 0.1-10}, and (E) platinum-based catalyst catalytic amount 2. The component (A) contains an average of 0.5 or more silicon atom-bonded alkenyl groups in the side chain of the molecular chain, and contains at least two silicon atom-bonded alkenyl groups in one molecule. The silicone rubber composition for a fluororesin-coated fixing roll according to claim 1, which is a linear diorganopolysiloxane. 3. The component (C) has the general formula: (In the formula, R ¹ is the same or different monovalent hydrocarbon group excluding an alkenyl group, R ² is an alkenyl group, m is an integer of 2 to 20, and n is an integer of 0 to 18. And m + n is an integer of 3 to 20), which is a cyclic diorganopolysiloxane containing at least 3 silicon-bonded alkenyl groups in one molecule. Item 2. A silicone rubber composition for a fluororesin-coated fixing roll according to Item 1. 4. The component (D) has the general formula: (In the formula, R ¹ is the same or different monovalent hydrocarbon group excluding alkenyl group, R ³ is the same or different monovalent hydrocarbon group excluding alkenyl group or hydrogen atom, and p is 0 Is an integer of 0 or more, and q is an integer of 0 or more, provided that when q is 0, both R ³ are hydrogen atoms.), And at least 2 silicon-bonded hydrogen atoms are contained in one molecule. The fluororubber-coated fixing roll silicone rubber composition according to claim 1, which is an organopolysiloxane containing atoms. 5. The outer peripheral surface of the roll shaft in the fluororesin-coated fixing roll comprising providing a fluorocarbon resin layer through the silicone rubber layer, 請the outer peripheral surface and fluorine resins interlayer roll axis
The silicone rubber composition according to claim 1 at 70 to 140 ° C.
A fixing roll coated with a fluororesin, which is cured .